The present invention relates to a method of preparing slurry from inorganic oxide and water and supplying the prepared slurry to polishing equipment and also relates to a system which realizes this method. Furthermore, the present invention relates to a method of preparing slurry from inorganic oxide and water and supplying the prepared slurry to polishing equipment for manufacturing semiconductor devices and also relates to a system which realizes this method.
Recently, slurry obtained by dispersing vapor-phase processed inorganic oxide particles in water has been used for polishing semiconductor devices, such as VLSI. This slurry is prepared to the desired composition, the desired concentration, the desired purity, etc., packed in a drum or other transport container, and shipped out to manufacturers who manufacture and polish semiconductor devices.
However, the method of packing the slurry for polishing in a drum or other transport container and shipped the same to manufacturers who manufacture and polish semiconductor devices has the following four problems (a) though (d):
(a) The slurry may dry or inorganic particles in the slurry may flocculate or precipitate during the transport or storage. As a result, the concentration and purity of the slurry or the particle size of the inorganic particles in the slurry may differ from those immediately after the preparation, and the desired polishing characteristics may not be obtained. In order to avoid this problem, it is necessary to thoroughly perform the quality control of the slurry during the transport and storage, or alternatively have the manufacturers who manufacture and polish semiconductor devices redo the filtration, refining and analysis of the slurry to reconfirm the quality of the slurry. However, it takes both the slurry manufacturers and the manufacturers who manufacture and polish semiconductor devices very high cost to perform this procedure.
(b) The desired polishing characteristics depend on the type, etc. of the semiconductor devices, etc. to be polished. For this reason, it is necessary to determine the composition, concentration, purity, pH, etc. of the slurry according to the object to be polished. However, it takes the slurry manufacturers very high cost to manufacture the slurry to the composition, concentration, purity, pH, etc. specified by the manufacturers who manufacture and polish semiconductor devices in their orders and supply the same to the manufacturers who manufacture and polish semiconductor devices on the other hand, a method of supplying the slurry prepared to the specified polishing characteristics (compositions, concentrations, purities, pHs, etc.) to the manufacturers who manufacture and polish semiconductor devices for their stock has a problem that the storage period may be longer and the above-described problem (a) may occur.
(c) The slurry which is low in stability is subject to quality deterioration during the storage or transport. Therefore, even if the polishing characteristics of the slurry has high polishing performance immediately after the manufacture, the quality of the slurry may deteriorate during the storage or transport, the polishing performance of the slurry may also deteriorate, and as a result, the slurry may no longer applicable to any industrial uses.
(d) Generally, the slurry for polishing is so low in concentration as 5 to 30%. This makes the slurry bulky and increases the transport cost.
In view of the problems described above, an object of the present invention is to eliminate the cost incurred by performing the strict quality control of the slurry during the transport or storage. Another object of the present invention is to make it possible to supply the slurry to the manufacturing system which manufactures and polishes semiconductor devices at the right time in the right quantity. Still another object of the present invention is to make it possible to make the instable slurry applicable to industrial uses. Still another object of the present invention is to prevent the slurry for polishing from deteriorating the cleanliness of the manufacturing system for semiconductor devices.
The method of manufacturing the slurry for polishing according to the present invention sequentially performs a process for dispersing inorganic oxide in water to obtain the slurry, a process for filtrating the obtained slurry, and a process for supplying the filtrated slurry to polishing equipment.
The method of manufacturing semiconductor devices according to the present invention sequentially performs a process for polishing semiconductor devices by using the supplied slurry following the supply process described above, and a process for detecting the polished condition of the polished semiconductor devices.
The system of manufacturing the slurry for polishing according to the present invention comprises a dispersing equipment for dispersing inorganic oxide in water to obtain the slurry by kneading the inorganic oxide with the water, a filtrating equipment provided behind the dispersing equipment for filtrating the slurry sent from the dispersing equipment, and a supplying equipment provided behind the filtrating equipment for supplying the slurry sent from the filtrating equipment to the polishing equipment.
The manufacturing system for semiconductor devices according to the present invention has polishing equipment provided behind the supplying equipment described above for polishing semiconductor devices by using the slurry continuously supplied from the supplying equipment described above.
Among the inorganic oxides which can be used in the present invention are metal oxide, such as silicon oxide, aluminum oxide, titanic oxide, zirconium oxide, antimony oxide, chromium oxide, germanium oxide, vanadium oxide, tungsten oxide, iron oxide, cerium oxide, manganese oxide and zinc oxide. Of these metal oxides, silicon oxide, aluminum oxide, titanic oxide and cerium oxide are particularly preferable. As the inorganic oxide used in the present invention, the inorganic oxide synthesized by the vapor-phase process, such as the fumed process for synthesizing silica by allowing silicon tetrachloride to react with hydrogen and oxygen and then hydrolyzed (high-temperature flame hydrolysis process) or the Nano-phase Technology""s process for synthesizing inorganic oxides particles by heating a metal to a temperature above the melting point of such metal to produce metal vapor and allowing such metal vapor to react with oxygen (metal evaporation and oxidation process), is preferable for its high purity. Alternatively, as the inorganic oxide used in the present invention, the inorganic oxide synthesized by the sol-gel process for synthesizing inorganic oxides by hydrolyzing metallic alkoxide may be used. The inorganic oxide synthesized by the fumed process is more preferable as such inorganic oxide is high in purity and also comparatively inexpensive. On the other hand, more than one type of inorganic oxide may be used in the mixed status.